Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
ve triet » va trien
su triet » su viet, su tien
vu sach » vu bach, su sach, vu khach
toc van » hoc van, tac van, oc van
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach y nang x hoi. hieu vien cac ((toc van) OR (toc san)) hanh vi ((ve triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y nang x hoi. hieu vien cac ((toc van) OR (toc san)) hanh vi ((ve triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach y nang x hoi. hieu vien cac ((toc van) OR (toc san)) hanh vi ((ve triet) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: vu sach y nang x hoi. hieu vien cac ((toc van) OR (toc san)) hanh vi ((ve triet) or (su triet))*.